From b5e7982ade668d18e07f51401d9af04d612c3be3 Mon Sep 17 00:00:00 2001 From: Ian Jackson Date: Wed, 7 Oct 2009 15:51:55 +0100 Subject: [PATCH] check for bs->drv in bdrv_flush (Christoph Hellwig) All the bdrv_ helpers should check for bs->drv being zero as that means there is no backend image open. bdrv_flush fails to perform that check and can thus cause NULL pointer dereferences. Found using qemu-io. Signed-off-by: Christoph Hellwig Signed-off-by: Anthony Liguori git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6943 c046a42c-6fe2-441c-8c8c-71466251a162 [ Backported from 6bbff9a0b495918309074ac60375be5f9dc868b3 by Stefano Stabellini. ] Signed-off-by: Ian Jackson (cherry picked from commit dddf85563a18db9ae83d59ad567f4d77d39da821) --- block.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block.c b/block.c index c3c44a95..3261225f 100644 --- a/block.c +++ b/block.c @@ -1071,6 +1071,8 @@ const char *bdrv_get_device_name(BlockDriverState *bs) int bdrv_flush(BlockDriverState *bs) { int ret = 0; + if (!bs->drv) + return -EINVAL; if (bs->drv->bdrv_flush) ret = bs->drv->bdrv_flush(bs); if (!ret && bs->backing_hd) -- 2.39.5